One problem related to catalytic convertor has been reported for the 2003 Chevrolet Cavalier. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Chevrolet Cavalier based on all problems reported for the 2003 Cavalier.
The catalytic converter has been damaged and needs to be replaced. The repair shop says that the damage was a result of unburned gasoline going into the catalytic converter when the coil failed. The coil assembly failed and two cylinders stopped firing. I only drove the car about one-mile to the repair shop after the failure (which happened suddenly). The coil assembly had to be replaced at a cost of about $400. After it was replaced, the "check engine" light came on and the repair shop says that the on-board computer diagnostics indicates that the catalytic converter has failed. The car cannot have its registration renewed without a functioning catalytic converter, which will cost about $500 to replace.